rm dup: use channel type names from libosmocore

In gsm_lchant_name(enum gsm_chan_t), use the gsm_chan_t_names value strings
from libosmocore instead of redefining the same strings. The list from
libosmocore is also more complete, including CCCH and PDTCH.

Add a todo comment to move to libosmocore.

In consequence, libosmogsm linkage needs to be added to osmo-bsc_mgcp,
mgcp_test, mgcp_transcoding_test and smpp_mirror, smpp_test.

Change-Id: If65ee7c0619cbc0acb0a15045bd5a969442c93cc
diff --git a/openbsc/src/libcommon/gsm_data_shared.c b/openbsc/src/libcommon/gsm_data_shared.c
index 9f9eb1e..e9eb4b0 100644
--- a/openbsc/src/libcommon/gsm_data_shared.c
+++ b/openbsc/src/libcommon/gsm_data_shared.c
@@ -92,19 +92,10 @@
 	return get_string_value(gsm_pchant_names, name);
 }
 
-const struct value_string gsm_lchant_names[8] = {
-	{ GSM_LCHAN_NONE,	"NONE" },
-	{ GSM_LCHAN_SDCCH,	"SDCCH" },
-	{ GSM_LCHAN_TCH_F,	"TCH/F" },
-	{ GSM_LCHAN_TCH_H,	"TCH/H" },
-	{ GSM_LCHAN_UNKNOWN,	"UNKNOWN" },
-	{ GSM_LCHAN_CBCH,	"CBCH" },
-	{ 0,			NULL }
-};
-
+/* TODO: move to libosmocore, next to gsm_chan_t_names? */
 const char *gsm_lchant_name(enum gsm_chan_t c)
 {
-	return get_value_string(gsm_lchant_names, c);
+	return get_value_string(gsm_chan_t_names, c);
 }
 
 static const struct value_string lchan_s_names[] = {